Funds are requested to support the travel of scientists to the ninth bi- annual Gordon Research Conference on Mutagenesis, which is to he held at Plymouth State College, Plymouth, New Hampshire. The Conference is scheduled from June 26 through July 1, 1994. The selected speakers are experts in the field of mutagenesis and the Conference will provide them with the opportunity to discuss their latest results and ideas. Of equal importance, the meeting serves as a forum for extensive interactions among all attending scientists through the Discussion Sessions and the Poster Presentations. The Conference is typically oversubscribed with attendance limited to 135 people. The participants are selected from universities, government research laboratories, regulatory agencies, research institutes, and industrial laboratories from all over the world. The 1994 Conference will explore the mechanisms by which cells mutate and the strategies organisms use to counter mutagenesis. Polymerases will he examined as key mediators of mutagenesis through their inherent infidelity in the copying of undamaged templates or through their inability to replicate faithfully at the sites of damage. The program will also explore how DNA lesions are recognized and enzymatically processed by cellular systems; recent NMR, X-ray and biochemical studies have begun to reveal high resolution static and dynamic views of these processes. DNA repair, a major cellular strategy to suppress mutagenesis, will he examined mainly in three areas: (i) recent advances in eukaryotic systems. (ii) mismatch repair. and (iii) mutagenesis and transcription coupled repair and mutagenesis. The meeting will also probe the origins of spontaneous mutations and, through a dedicated session on lesion structure and mutagenesis, try to bridge the gap between chemistry and genetics. Mutations are the source of most cancers and all genetic diseases and we shall explore this relationship in another dedicated session. The meeting will end with an examination of adaptive mutagenesis, an old phenomenon recently rediscovered, and now thought to play a role in the adaptation of organisms to genetic stress. In summary, this Conference will examine mutagenesis from the chemical, biochemical, and genetic viewpoints. The field as a whole is important component of the discipline of biology as it is through mutagenesis that life-forms evolve. Furthermore, the field is important to human health because mutations induced either spontaneously or by exogenous damage appear to initiate of facilitate the progression of a host of human diseases.